Internal tubes of the type mentioned at the outset for tanks as well as internal tubes for fuel tanks of automobiles are already known from practice in various designs. It is also already known to embody these internal tubes for tanks in a multilayer design. However, we have found that the internal tubes for tanks known from practice oftentimes have the drawback that components are washed out of the walls of the internal tube for tanks as a result of contact with fluids, for example with fuel. This can occur as a result of the fluid flowing in the tube on the one hand and as a result of the fluid that is located within the tank and comes in contact with the internal tube for tanks on the other hand. These washouts impair the functionality of the fuel system in a disadvantageous manner and can lead to damage and/or failure over the long term. In addition, the internal tubes for tanks that are known from practice often have elaborate constructions and are therefore costly to manufacture. Furthermore, we have found that the durability of the known internal tubes for tanks in the presence of mechanical and chemical loads often leaves something to be desired.